Face Preparation
There are several differences between the preparation of XP & AT faces
• Pre-Pressurisation More Common
• Polishing Techniues
 
The #perating Pressure $etermines the %eed for Pre-Pressurisation
Pre-Pressurisation Produces an nitial $istortion on the Face 'hich can Then be Polished out Prior to Test
Pre-Pressurisation is Carried out in the rig Shown !elow( Alternativel) it can be Completed in the Test Cell
Pre-Pressurisation  Criteria
Polishing
$ue to the *eometr) of the XP carbon it is #ften %ecessar) to Polish the Carbon as Shown !elow
+#A$
$FSM Spra)
'ith the XP $esign it was Found That as the Carbon Collapsed nder Pressure Some Frictional Problems 'ere Present !etween the !ac" of the Face & the Pol)mer Seal
To #vercome This Problem a Compound .now as $FSM Spra) is Spra)ed onto the !ac" of the Face
The Spra) is sed as an Aerosol & Must be sed in a 'ell /entilated Area
The Spra) Coats the !ac" of the Face 'ith a *re) Compound
This Coating MST  be Smooth & Flat
 
 
12134$154256
%ote 7 f Material #ther Than 256 *lass TFM is to be sed Contact 8ngineering at Slough
Si9e Code 121(3 mm
Material Code *lass TFM
Pol)mer T)pe !ehind Seat
*>1 - ,etro-Fittable
Fitting Pol)mer Seals
As 'ith all *as Seal Components Firstl) Chec" That !oth the Pol)mer Seal & Metal Part are Clean & Free From $amage
The Pol)mer Fits 8asil) into the *roove
$15 - !ehind Seat
 
• Pol)mers 'ill %eed 8asing nto *roove
• After Cooling the Pol)mers 'ill Contract to *ive a Secure fit
• 'hen sing a $12 in the !ore@ fit as )ou 'ould an # ,ing
• After Fitting 8nsure Pol)mers are Free From $amage
 
• Fit Pol)mer !efore !uild for !alance
• Pol)mers 'ill %eed ?eating up
• After Fitting 8nsure Pol)mers are Free From $amage
Fitting Tool
Cover Tolerance Strip *rooves 'ith Tape to Avoid $amaging the Pol)mer
This Procedure is +aid $own in '*S Section F
 
Fitting Pol)mer Seals
#nce the Pol)mer is +oosel) in the *roove ?eat & Allow to Cool Several Times sing The ?eat *un
#nce the Pol)mer Starts to Fit the *roove nvert the Spacer Sleeve & +ower #ver Main Sleeve
Again sing the ?eat *un ?eat The #$ of the Spacer Sleeve 1-B Times
+eave for B6 Minutes
 
• The $1: Pol)mer is a ,etained $esign
• 8nsure Pol)mer is Fitted 'ith the ,ed Mar" Facing p
• Fit Pol)mer According to '*S Section .
t is 8ssential That the Correct Pol)mer Stand #ut is Achieved
6(1 - 6(12 mm
• The F=2 Pol)mer is a ,etained $esign
• The *>1 is A ,etro-fittable /ersion of the F=2
 
Fitting Pol)mer Seals #nce the Pol)mer is Fitted the Assembl) Must be Placed in an #ven at 166 degrees C for ?our
!efore This is $one The Carrier is Placed in Position Through the !ac" of the ,etainer as Shown
After the Assembl) has Cooled $own the Seal ?ead Test is Carried out(
This Chec"s the Movement of the Seal ?ead
 
Seal ?ead Testing Seal ?ead Testing 8nsures That the Pol)mer Seal is Producing the Correct Amount of Aial ,esistance on the Carrier
Too Much 'ill ,esult in ?ang-p
Too +ittle 'ill Allow +ea"age !low !) on Test
Seal ?ead Tester
 
Tools ,euired
The Assembl) of an XP is /er) Similar to That of an AT 
$ifferences are7
• Fitting Tool %eeded for Fitting of nder Spacer Sleeve Pol)mer
• Fitting Tool %eeded for Assembl) of Seal ?ead
 
Fitting Tools
8ach $ifferent $esign of Carrier & Sleeve Must ?ave An ndividual Fitting Tool
Current Pol)mer Fitting Tools
Testing XP0s
The XP Seal b) $esign is More ,obust Than the AT( t 'ill 'ithstand Much *reater Pressures & a Much ?igher $ecompression ,ate(
The XP Seal is /er) Sensitive to Slight Changes in Pressure Particuall) at ?igh Pressure@
A Small $rop in Pressure 'ill ,esult in A +ea"age ncrease@ #nce the Pressure ,ises Again the +ea"age 'ill ,educe
This is ,eferred to as C)cling
 
#n Completion of Test the Seals ndergo a Strip & nspection
t is 8ssential to Strip the Seal ?eads to 8amine the Carriers for !oth 'ear & Fretting